<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      * {
        padding: 0;
        margin: 0;
        box-sizing: border-box;
      }
      .header,
      .footer {
        position: absolute;
        width: 100%;
        height: 100px;
        background: red;
      }
      .header {
        top: 0;
      }
      .footer {
        bottom: 0;
      }
      .main {
        position: absolute;
        top: 100px;
        bottom: 100px;
        width: 100%;
      }
      .left,
      .right {
        width: 100px;
        height: 100%;
        background: blue;
      }
      .left {
        float: left;
      }
      .right {
        float: right;
      }
      .center {
        margin: 0 100px;
        height: 100%;
        background: purple;
      }
    </style>
  </head>
  <body>
    <!-- 未实现 -->
    <div class="header"></div>
    <div class="main">
      <div class="left"></div>
      <div class="right"></div>
      <div class="center"></div>
    </div>
    <div class="footer"></div>
  </body>
</html>
